Method for forming a fine pattern in a semicondutor device

Abstract

A method for forming a fine pattern a semiconductor device includes the steps of forming a first photoresist pattern over a semiconductor substrate having an underlying layer; coating a pattern hardening coating agent over the first photoresist pattern, thereby forming a pattern hardening film; forming a second photoresist film over the resulting structure; and selectively exposing and developing the second photoresist film, thereby forming a second photoresist pattern to be defined between neighboring first photoresist pattern.

1. A method for forming a fine pattern in a semiconductor device, the method comprising the steps of:
 forming first photoresist patterns over a semiconductor substrate having an underlying layer; 
 coating a pattern hardening coating agent over the first photoresist patterns, and then baking the pattern hardening coating agent at a temperature ranging from 150° C. to 300° C., 
 wherein the hardening coating agent comprises an addition polymer consisting of a 2,2,3,4,4,4-hexafluorobutyl methacrylate repeating unit and a glycidyl methacrylate repeating unit, an organic solvent, and 2-hydroxycyclohexyl p-toluenesulfonate, to form a pattern hardening film; 
 forming a second photoresist film over the pattern hardening film; and 
 selectively exposing and developing the second photoresist film, thereby forming a second photoresist pattern to be defined between neighboring first photoresist patterns. 
 
     
     
       2. The method according to  claim 1 , wherein the organic solvent comprises an alcohol having five or more carbon atoms. 
     
     
       3. The method according to  claim 1 , wherein the pattern hardening coating agent comprises the copolymer in an amount ranging from 1 to 5 weight parts, based on 100 weight parts of the coating agent. 
     
     
       4. The method according to  claim 1 , wherein the step of baking the pattern hardening coating agent is performed for 30 seconds to 180 seconds. 
     
     
       5. The method according to  claim 1 , wherein the step of forming the first photoresist pattern comprises:
 coating a first photoresist composition over the semiconductor substrate, thereby forming a first photoresist film; 
 selectively exposing the first photoresist film with an exposure energy ranging from 10 mJ/cm 2  to 200 mJ/cm 2  using a first exposure mask; 
 post-baking the exposed photoresist film at a temperature ranging from 90° C. to 150° C. for 30 seconds to 180 seconds; and 
 developing the baked photoresist film. 
 
     
     
       6. The method according to  claim 5 , wherein the step of forming the second photoresist pattern comprises:
 selectively exposing the second photoresist film with an exposure energy ranging from 10 mJ/cm 2  to 200 mJ/cm 2  using a second exposure mask; 
 post-baking the exposed photoresist film at a temperature ranging from 90° C. to 150° C. for 30 seconds to 180 seconds; and 
 developing the baked photoresist film. 
 
     
     
       7. The method according to  claim 6 , wherein the second exposure mask is the same as the first exposure mask. 
     
     
       8. The method according to  claim 6 , wherein the second exposure mask is different from the first exposure mask. 
     
     
       9. The method according to  claim 1 , wherein the step of forming the first photoresist pattern is performed using immersion lithography equipment. 
     
     
       10. The method according to  claim 1 , wherein the step of exposing and developing the second photoresist film is performed using immersion lithography equipment. 
     
     
       11. The method according to  claim 1 , wherein a pitch between the first photoresist patterns is A, and a pitch between the first photoresist pattern and the second photoresist pattern is A/2.